None
1. Field of Invention
The present invention is an integrated unit liquified gas fill station attached to a cryogenic storage tank and pump which provides for a controlled delivery of a programed weighted amount of a cryogenic liquified gas, primarily carbon dioxide, to empty transfer cylinders at the time of initial filling or subsequent refilling, to prevent dangerous overfilling of the cylinders resulting in over-pressure explosions of the transfer cylinders, the liquified gas fill station providing a programmable tare scale upon which the transfer cylinder is positioned, a cryogenic liquified gas bypass circulating system and a cryogenic liquified gas delivery system wherein the station operator selects a weighed amount of gas appropriate for the capacity of the transfer cylinder to be programmed into the station, delivering the measured amount of cryogenic liquified gas to the attached transfer cylinder resting on the tare scale, and filling the transfer cylinder with the precise measured and weighed amount of cryogenic liquified gas after which the station automatically stops the filling process when the programmed weight of liquified gas has been delivered to the transfer cylinder.
2. Description of Prior Art
The following United States patents were discovered and are disclosed within this application for utility patent. All relate to cryogenic liquid dispensing devices, specifically devices delivering, at least in part, compressed carbon dioxide gas. However, these devices do not disclose any automated system for the delivery of a programmable amount of the liquified gas to transfer cylinders by weight using the same material components.
The first referenced patent, U.S. Pat. No. 5,953,923 to Davies, discloses a fluid dispensing apparatus and method of dispensing the fluid, employing the use of a scale measuring device, primarily with regard to the deliver of refrigerant to a refrigerant system, as in automobiles. The disclosed device having a containing means including a containing chamber containing the delivery fluid and dispensing chamber containing a buffer gas separated by some type of deformable membrane which in turn delivers the pre-measured gas to a dispensing capsule. There are plural valves in this system involved in the delivery process, requiring a coordination of the opening and closing of these multiple valves in rapid succession to carry out its precision measurement. The present delivery system has only one valve diverging the liquid gas from the bypass system to the delivery system and the attached transfer system without any multi-chambered containing means or other gas involvement and is a direct delivery system to the transfer cylinder.
U.S. Pat. No. 4,100,759 to Tyree, Jr. deals more specifically with a gas recovery system contained on a vehicle, this system also having multiple valves and inner compression systems to cause a circulating gas to resume a liquid form by the creation of a carbon dioxide xe2x80x9csnowxe2x80x9d. This system does not provide delivery of the gas to an outside transfer cylinder, and does not involve any weighed measurement of gas delivery.
U.S. Pat. No. 5,916,246 to Viegas, discloses a two step pressure reduction system for the delivery of high pressure gas to a lower pressure container, having a first, second and third pressure reduction regulator, and muffler to dampen the sound of vented gas, with pressure relief valves, hoses, manually activated bleed valves. It also has an electronic automated filling cutoff, but it is distinguished because it determines the cutoff by the volume of the tank, using a tank level sensor, which senses the full condition of the tank, causing the gas to be diverted to a solenoid operated purge valve. The present invention is distinguished by its electronic control sensor determining the xe2x80x9cfullxe2x80x9d tank when a programmed weight is attained, measuring the weight of the gas delivered to the transport tank being filled. It also is distinguished by its solenoid diverting gas either to the circulating tubing or the delivery tubing, not diverting the gas to the open air or atmosphere, except for the purge mechanism to empty the minute contents of the deliver hose after the filling transport tank is completed.
In U.S. Pat. No. 6,354,088 to Emmer, an LP gas delivery system is disclosed employing a microprocessor controlled fill mechanism with a heat exchange apparatus to deliver saturated fuel to a tank, the delivery tank having the fill sensor which communicates the capacity data to the delivery system to optimize the saturation of the fuel to the tank. The heat exchanger is used to increase the pressure of the gas in the delivery tank, or saturate the fuel.
In the cryogenic gas industry, the delivery of a precise amount of a cryogenic liquified gas to a gas transport cylinder is critical. In the event that a very small amount of a cryogenic gas is place within a transport cylinder above the express capacity of such transport cylinder, the risk of a catastrophic explosion can be enhance exponentially. In order to prevent such overfilling, the present invention seeks to accomplish the controlled and measured filling of the transport tanks using a system that incorporates a tare scale allowing for the measurement of a programmed amount of liquified gas to fill the transport cylinders to a safe and uniform weighed volume of cryogenic liquified gas.
The primary objective of the invention is to provide a cryogenic liquified gas fill station that provides a pre-determined weighted volume of liquified gas to be delivered to a transport tank from a bulk tank storage tank which automatically stops delivery of the liquified gas when the programmed volume is reached, returning the majority of the liquified gas in the system to the bulk storage tank at the conclusion of the filling process.
A second objective of the invention is to provide the liquified gas fill station with a three way solenoid valve integrated with a control manifold that circulates the cryogenic gas in the fill station to and from the bulk storage tank through circulating lines until delivery to a transport tank is commenced by the activation of the start relay, at which time the cryogenic liquified gas is diverted from the circulating lines to the delivery hose by the three way solenoid, filling the transport tank until the programmed measured weight of cryogenic is attained, the three way solenoid then returning the flow of the cryogenic liquified gas to the circulating lines.
A third objective of the invention is to provide this liquified gas fill station with a purge valve to clear a minute amount of gas left in the manifold to relieve pressure when the fill station is not in use, and an emergency bypass valve to return any overfill liquified gas to the bulk storage tank in the event an overfill occurs due to mis-programming of the system, the goal of these two objective to prevent any release of the cryogenic gas to the environment or the air in the workplace where the fill station is located.